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ALSA: hda: Fix too short HDMI/DP chmap reporting

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We got a regression report about the HD-audio HDMI chmap, where some
surround channels are reported as UNKNOWN.  The git bisection pointed
the culprit at the commit 9b3dc8aa3f ("ALSA: hda - Register chmap
obj as priv data instead of codec").  The story behind scene is like
this:

- While moving the code out of the legacy HDA to the HDA common place,
  the patch modifies the code to obtain the chmap array indirectly in
  a byte array, and it expands it to kctl value array.
- At the latter operation, the size of the array is wrongly passed by
  sizeof() to the pointer.
- It can be 4 on 32bit arch, thus too short for 6+ channels.
  (And that's the reason why it didn't hit other persons; it's 8 on
  64bit arch, thus it's usually enough.)

The code was further changed meanwhile, but the problem persisted.
Let's fix it by correctly evaluating the array size.

Fixes: 9b3dc8aa3f ("ALSA: hda - Register chmap obj as priv data instead of codec")
Reported-by: VDR User <user.vdr@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Takashi Iwai 2017-11-17 12:08:40 +01:00
parent b2500b584c
commit c2432466f5
1 changed files with 1 additions and 1 deletions
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2
sound/hda/hdmi_chmap.c
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@ -746,7 +746,7 @@ static int hdmi_chmap_ctl_get(struct snd_kcontrol *kcontrol,
memset(pcm_chmap, 0, sizeof(pcm_chmap));
chmap->ops.get_chmap(chmap->hdac, pcm_idx, pcm_chmap);
for (i = 0; i < sizeof(chmap); i++)
for (i = 0; i < ARRAY_SIZE(pcm_chmap); i++)
ucontrol->value.integer.value[i] = pcm_chmap[i];
return 0;